Internal bore gauge checking device



June 26, 1951 A. EISELE INTERNAL BORE GAUGE CHECKING DEVICE Filed NOV, 25, 1948 :inventor 4f/few fsa/2 Gttornegs Patented June 26, 1951 El)N S'IXBUT13S` PATENT O F FICE INTERNAL BGRGAUGE CHECKING' DEVICE Andrew Eisele, Detroit, Mich. Application Novemberi23, 1948, SerialNo. 61,700

(Cl. 33T-443i 2 Claims.

rIhis inventionirelates to gauges and,v inparticular, to gauge block'ho'lders.

One object' of this invention is to provide; anY

internal bore gauge checkingdevice which con.-

sistsof` a holder iorprecisiongauge blocksand adapted to clamp two or'more such' blocks-adding` up to the diameter to be checked by the internal bore gauge;

AnotherobjectistcA provide an internal bore gauge checking device oi the foregoingcharacter wherein" the' gauge blocks are' clamped between' j aws;` oneof which hasv a concave extensionV surfaceealignedwith the outside surfaceof one of:

the outermost' gauge blocks', the other' jaw having' an extension surface alignedL with theoutside surface-of theother outermost' gauge blockl so that' an internal bore gauge inserted between the two extension surfaces will be applied to a= diameterwhichis the same as the distance between the saidoutside sur-faces:

Another object is to provide an internal bore gaugechecling device oi-theforegoingcharacter wherein one of the jaws has a-notch' or'groovev gaugechecking device according, to a preferredAl form ofthe invention;

Figure 2 is a front' elevation, partly in section, of the checking device shown in Figure l;

Figure 3 is a cross-section through the checking device of Figures 1 and 2, taken along the line 3-3 therein; and

Figure 4 is a perspective view of one of the gauge block clamping jaws.

Referring to the drawings in detail, Figure l shows an internal bore gauge checking device, generally designated Il), as consisting generally of a frame II slotted to receive a pair of jaws I2 and I3 between which precision gauge blocks I4 are adapted to be clamped. The frame II consists of a pair of parallel side bars I5 and I6 separated from one another by spacing blocks I'I and I3 at their opposite ends secured together in assembly by fasteners I9. The bars I5 and 2. I6 form` guide railsforthe jaws I2 and I3 and. the bar` I 6 is slotted` as at 2U to permit added: visibility oftheblocks I=1` andjawsIZ and I 3:

TheY spacing block I'lfisboredand threaded as at 2I to receivethe shank 2201E aclampingrscrewY 23"; The-latter'isintwo parts, havingits for` wardendr bored and threadedas at 24 to receivethe'threadedshank 2'5 on the reducedk diameterk end" portion of a contact pin or stem 261(Figurer 2). The'stem or pins-'26serve as extenslonrods and are-= supplied in different lengths so as to permit the-jaws I2 and I3` to-be separatedY by widely varying distances r without havingan excessively long portion of the screw 23 projecting from* thel'instrument.

Thejaws' l2"A and l'are of`somewhat similar construction butldiler in certain dimensionsas setffor-thbelow: The jawslhave Shanks 21? withl twovparallel side wallsor surfaces 28v (Figure 4'); The two' remaining opposite side` walls 2.9i are. slightly roof-l-shaped and-havecentrali parallel lands -13lwith oppositely inclined `or'` tapering portionsw 3TI on either sidethereofso as to` providen aislight clearance-and'. to givea limitedlamount! of Vself#aligningmotion` when .thejaw is i inserted betweenfthebars Iand` I6.. The'taperis veryV slight and is of the order of .001 inch, it` being exaggerated" in` the drawingsxin order` to: show itlclearl'y..

The jaws` I2 and I13 are provided withLhea'ds` 32-fon theendsloftheushanksl21; these heads 321 on: oneA side having an partiallyf concave cylindrical,` surface 33 and on4 ther other side: having? a groove. or slot'. 34C with a partially cylindrical` bottom wall. The' surfaces 33 and (i5v onuthel heads32` ofi the two` jaws: I 2 vand I 3i are offsimilarf shapeil buty different radii off curvature in` order. tozfiti dilerent` diam'eters'of` internal-bore gauges. Each concave surface 33 or 35 at its central point is exactly in line with and merges into the adjacent surface 28 of the shank 21 so that a, knifeedge straight edge laid lengthwise along the surface 28 (Figure 4) would also accurately nt the surface 33 at the location where the two surfaces 28 and 33 are on the same level..

The extension rod or stem 2B does not directly engage the shank 21 of the jaw I2, but a clamping block 36 is interposed therebetween so as to prevent injury to the shank 21. The clamping block 36 is provided with a side arm 31 which extends snugly but slidably into the slot 2U, the opposite edges of which serve as guide surfaces for the arm 31. Relief grooves 38 are provided at the corners or edges of the slot 20 (Figure 3).

In the use of the invention, it will of course be known in .advance the diameter on which it is desired to check the internal bore gauge G, the measuring head only of which is shown in dotted lines in Figures 1 and 2. Precision gauge blocks III are selected of such dimensions that when they are stacked they add up to the desired diameter to be checked. The blocks I4, two of which are shown for purposes of illustration, are inserted between the Shanks 27 of the jaws I2 and I3 in the space between the parallel side bars I5 and I6 and rest against the surfaces 28 of the jaw shanks 2. The clamping block 36 is then forced into clamping engagement with the gauge blocks II by turning the clamping screw 23. The concave surfaces 33 and 35. at their midportions are now exactly in line with the outer sides of the precision gauge blocks I4.

The internal bore gauge G is then inserted in the device with its fixed pin F seated in the groove 34 against the concave surface 35 .and its mov- Vable pin M engaging the center of the concave surface 33. The locating or centering pins L move inward or outward to center the movable pin M in the cylindrical surface 33. The reading of the dial indicator (not shown) with which the internal bore gauge G is equipped should be the same as the distance between the opposite sides of the precision gauge blocks I4, otherwise the gauge is giving an erroneous reading. The dial or needle of the dial indicator may then be 4 the single pin F is centered in the slot 34 on the other side. Y

What I claim is:

1. An internal bore gauge checking device for use with a precision gauge block holder having gauge blocks mounted in a guideway'therein, said checking device comprising a pair of opposed jaws with shanks slidably engaging said guideway, said shanks'having opposed portions adapted to engage one or more precision gauge blocks placed therebetween, said jaws also having opposed contact surfaces engageable with the contact pins of the internal bore gauge to be checked, and clamping mechanism engaging and urging said jaws into clamping engagement with said gauge blocks, said shanks having slightly roof-shaped side surfaces inclined in opposite directions from the central portions thereof for adjusted to compensate for the error and to insure that the gauge G will read accurately when placed in an actual bore.

Hitherto it has been found diicult to check Yinternal bore gauges accurately other than by actual ring gauges. Ring gauges, however, are inexible and therefore must be available in several diameters. The checking of internal bore gauges between flat surfaces has been found inaccurate in practice, as the gauge gives a different result when applied to a bore. In other words, when the round-tipped pins of the bore gauge are adjusted between fiat surfaces of at gauge blocks and then applied to a cylindrical bore, the readings of the gauge do not agree accurately.

The gauge checking device of the present invention, however,Y provides as many different diameters as there are gauge block combinations. Several sets of jaws with different curvatures of increasing radii on the jaws and for increasing widths of blocks give the device a wide range of diameters capable of being checked. With four sets of jaws, for example, diameters from 1/2 an inch to 14 inches may be checked. The arcuate or cylindrical surface on the one jaw holds the free pins L and M centered on one side, whereas self-alignment thereof in said guideway.

2. An internal bore'gauge checking device for use with a precision gauge block holder having gauge blocks mounted ina guideway therein, said checking device comprising a pair of opposed jaws with Shanks slidably engaging said guideway, said shanks having opposed portions adapted to engage one or more precision gauge blocks placed therebetween, said jaws also having opposed contact surfaces engageable with the contact pins of the internal bore gauge to be checked, and clamping mechanism engaging and urging said jaws into clamping engagement with said gauge blocks, said shanks having slightly roof-shaped side surfaces inclined in opposite directions from the central portions thereof with substantially parallel lands between said oppositely-inclined surfaces for self-alignment thereof in said guideway.

ANDREW EISELE.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS OTHER REFERENCES Y Publication, Gages, Standard Gage Cc., Inc., Catalog No. 3, Copyright, 1927.

Publication, Johansson Gage Blocks and Ac cessories, Catalog No. 17, page 23. Y Y 

